For example, JP2008-290625A discloses a seat slide apparatus for a vehicle. The vehicle is a so-called three-row seat vehicle having a front seat, a second-row seat and a third-row seat, in which a lower rail fixed on a vehicle floor with extending in the front-rear direction of the vehicle is mounted in a range corresponding to normal positions of the second-row and third-row seats. An upper rail, which is fixed to the second-row seat and is configured to move along the lower rail, is provided to move over a wide range (range corresponding to the normal positions of the second-row and third-row seats) in the front-rear direction of the vehicle.
Also, JP 3678191B discloses a seat slide apparatus for a vehicle. In the seat slide apparatus for a vehicle, the upper rail has a pair of rolling members in the front-rear direction and a shoe. The pair of rolling members allows the upper rail to move relatively to the lower rail in the front-rear direction. The shoe has a sliding contact part that slidingly contacts a lower surface of the lower rail by own elastic force so as to suppress the upper rail from rattling upwards with respect to the lower rail between the rolling members. According to the seat slide apparatus for a vehicle, the smooth moving is secured while the upper rail is suppressed from rattling.
There is a so-called three-row seat vehicle in which the vehicle floor is bent between the normal position of the front seat and the normal position of the second-row seat, and a rear side thereof is inclined. However, in the related seat slide apparatus for a vehicle, a planar vehicle floor is generally assumed, so that the lower rail is linearly designed. The design is not corresponding to the bending (inclination) of the vehicle floor, and a problem, which occurs when the lower rail including the bent part is provided, is not considered at all. Specifically, the problem, which occurs with regard to the shoe provided between the rolling members of the upper rail, is not also considered. In a related seat slide apparatus for a vehicle in which the lower rail is provided to avoid the bent part, a problem occurs in that the degree of moving freedom of the front seat in the front-rear direction is to be limited.
A need thus exists for a seat slide apparatus for a vehicle which is not susceptible to the drawback mentioned above.